INFO: task kworker/u8:14:3051 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:14 state:D stack:19720 pid:3051 tgid:3051 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16ec/0x5620 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1662 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline] __rt_mutex_slowlock_locked+0x1f28/0x2550 kernel/locking/rtmutex.c:1779 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1819 __rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:245 f2fs_down_write fs/f2fs/f2fs.h:2411 [inline] f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline] f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095 f2fs_balance_fs_bg+0x574/0x9d0 fs/f2fs/segment.c:545 f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2257 do_writepages+0x32e/0x550 mm/page-writeback.c:2571 __writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764 writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2132 wb_writeback+0x459/0xb00 fs/fs-writeback.c:2243 wb_check_old_data_flush fs/fs-writeback.c:2347 [inline] wb_do_writeback fs/fs-writeback.c:2400 [inline] wb_workfn+0xb17/0xf20 fs/fs-writeback.c:2428 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/37: #0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:4/66: #0: ffff888032407138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888032407138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000151fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000151fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4206 6 locks held by kworker/u8:6/152: #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90003927c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90003927c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8f349020 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673 #3: ffff888060e4e160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff888060e4e160 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline] #3: ffff888060e4e160 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:555 #4: ffff88803d3dc310 (&devlink->lock_key#29){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline] #4: ffff88803d3dc310 (&devlink->lock_key#29){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline] #4: ffff88803d3dc310 (&devlink->lock_key#29){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:555 #5: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #5: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2162 7 locks held by kworker/u8:12/1577: 4 locks held by kworker/u8:14/3051: #0: ffff88801eefe938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801eefe938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000e267c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000e267c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffff888037d0a0d0 (&type->s_umount_key#82){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff888032ed1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2411 [inline] #3: ffff888032ed1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline] #3: ffff888032ed1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095 2 locks held by getty/5359: #0: ffff88803685f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211 4 locks held by syz.0.205/8305: 2 locks held by syz.9.255/9123: #0: ffff888037d0a0d0 (&type->s_umount_key#82){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888037d0a0d0 (&type->s_umount_key#82){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 #1: ffff888025abe8c0 ( &bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:396 [inline] &bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x209/0xc30 fs/fs-writeback.c:2942 1 lock held by udevd/9127: #0: ffff88803758e480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 2 locks held by kworker/u8:2/9746: #0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801a074138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90004e67c40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90004e67c40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 1 lock held by syz-executor/10122: #0: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65f/0xe30 net/ipv6/addrconf.c:5039 9 locks held by syz-executor/10413: 2 locks held by syz-executor/10565: #0: ffffffff8f349020 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8f357d78 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d7/0x840 net/ipv4/ip_tunnel.c:1146 3 locks held by syz.6.398/10605: 9 locks held by syz.4.400/10615: 1 lock held by dhcpcd-run-hook/10614: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 10413 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline] RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237 Code: 13 25 ff 0f 00 00 39 05 bf 25 d2 11 73 06 89 05 b7 25 d2 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 70 53 e9 RSP: 0018:ffffc90003d367a0 EFLAGS: 00000002 RAX: ffffffff9607d518 RBX: 00000000000003cd RCX: 0000000000000022 RDX: ffffffff95f6e268 RSI: ffff88803860cb30 RDI: 00000000000003cd RBP: cfbc72cd63f240d3 R08: ffffc90003d36768 R09: 0000000000000020 R10: 0000000000000100 R11: ffffffff81a0b320 R12: ffffffff95fa4eb8 R13: ffffffff9313c690 R14: ffff88803860bd80 R15: 0000000000000021 FS: 00005555654f0500(0000) GS:ffff888126273000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1ea529d000 CR3: 000000007ebca000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73 ktime_get+0x45/0x220 kernel/time/timekeeping.c:965 clockevents_program_event+0x290/0x630 kernel/time/clockevents.c:363 __hrtimer_reprogram kernel/time/hrtimer.c:735 [inline] hrtimer_force_reprogram kernel/time/hrtimer.c:746 [inline] __hrtimer_start_range_ns kernel/time/hrtimer.c:1458 [inline] hrtimer_start_range_ns+0xb28/0xef0 kernel/time/hrtimer.c:1491 hrtimer_start include/linux/hrtimer.h:220 [inline] hrtick_cond_restart kernel/sched/core.c:924 [inline] hrtick_schedule_exit kernel/sched/core.c:986 [inline] finish_lock_switch kernel/sched/core.c:5124 [inline] finish_task_switch+0x3cd/0xbe0 kernel/sched/core.c:5243 context_switch kernel/sched/core.c:5391 [inline] __schedule+0x16f4/0x5620 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 9e ca 10 00 00 00 00 eb b5 e8 c5 ac 7c 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 a5 57 ca 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 4a 72 80 09 cc 48 8d 3d 12 b5 eb RSP: 0018:ffffc90003d36f00 EFLAGS: 00000286 RAX: d97cf9936e79ae00 RBX: 0000000000000283 RCX: 0000000000000046 RDX: 00000000493cd921 RSI: ffffffff8d8651fc RDI: ffffffff8ba752e0 RBP: ffff88803860cab8 R08: ffffffff8187b1bc R09: ffffffff8dfc8080 R10: 0000000000000000 R11: fffffbfff1f11fbf R12: 0000000000000009 R13: 0000000000000009 R14: ffffffff8de5f240 R15: ffff88803860bd80 __local_bh_enable_ip+0x98/0x2b0 kernel/softirq.c:268 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x1aa/0x7d0 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] inet6_netconf_notify_devconf+0x10f/0x1d0 net/ipv6/addrconf.c:593 __addrconf_sysctl_register+0x45a/0x4d0 net/ipv6/addrconf.c:7346 addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7383 ipv6_add_dev+0xd64/0x1400 net/ipv6/addrconf.c:460 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3662 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x18d5/0x1ed0 net/core/dev.c:11461 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1069 [inline] nsim_create+0xbff/0x1170 drivers/net/netdevsim/netdev.c:1151 __nsim_dev_port_add+0x857/0xd30 drivers/net/netdevsim/dev.c:1509 nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1570 nsim_drv_probe+0x90d/0xc30 drivers/net/netdevsim/dev.c:1731 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:709 __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871 driver_probe_device+0x4f/0x240 drivers/base/dd.c:901 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500 __device_attach+0x2c8/0x450 drivers/base/dd.c:1101 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x12d/0x220 drivers/base/bus.c:613 device_add+0x7e9/0xbb0 drivers/base/core.c:3706 nsim_bus_dev_new drivers/net/netdevsim/bus.c:471 [inline] new_device_store+0x37b/0x710 drivers/net/netdevsim/bus.c:191 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x629/0xba0 fs/read_write.c:688 ksys_write+0x156/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd0dbadd68e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007ffef4d3aad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00005555654f0500 RCX: 00007fd0dbadd68e RDX: 0000000000000003 RSI: 00007ffef4d3ab60 RDI: 0000000000000005 RBP: 00007fd0dbbb3616 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffef4d3ab60 R14: 00007fd0dc8c4620 R15: 0000000000000003 EXT4-fs (loop4): error count since last fsck: 2 EXT4-fs (loop4): last error at time 1779062725: ext4_acquire_dquot:7034